Welcome to the latest edition of Ask John where renowned rugby historian John Griffiths will answer any rugby-related query you have!

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In this edition, John Griffiths looks at World Cup final referees, pool stage winning margins, try-scoring finalists, debutants in the final of rugby's global gatherings and Test captains.

Craig Joubert was said to be the youngest RWC Final referee. How old were the previous RWC Final referees?Chris, England

Craig Joubert was 33 at the time of the Final last month (he is 34 on November 8th) and became the youngest referee to take control of a RWC Final. He was younger than some of the players who took part - a RWC Final first.

The only thirty-something before him was the late Kerry Fitzgerald of Australia who took charge of the 1987 NZ-France Final. He was in his late thirties at the time.

Kerry died of a heart attack in his Brisbane office a couple of months after returning home from reffing at the 1991 RWC tournament. His last Test was the Scotland-England semi-final at Murrayfield in late-October 1991. He was 43 at the time of his death.

Derek Bevan (1991), Ed Morrison (1995), André Watson (1999 and 2003) and Alain Rolland (2007) were in their forties at the time of their RWC Final appointments

How have the average winning margins in the pool rounds of the various RWC tournaments compared? Trevor Thomas, Wales

After the dip from 1987 to 1991, points margins rose in 1995 after the value of the try had been increased from four to five points (in 1992).

The average winning margin in the pool stages has fallen steadily since 2003.

How many RWC Finals of the professional era have been won by the team scoring the majority of tries?David Martin, England

One out of five: Australia's 35-12 (two tries to nil) win against France at Cardiff in 1999 is the only Final since the dawn of the professional era that has been won by the team scoring the majority of tries.

Both of South Africa's wins (1995 against New Zealand and 2007 against England) were in try-less matches while England (2003) and New Zealand (last month) "drew" their Finals one-all on tries, relying on successful kicks to win their matches.

In the two Finals that preceded 1995, New Zealand beat France 29-9 (three tries to one) in 1987 and Australia beat England 12-6 (one-nil on tries) in 1991, when loose-head Tony Daly crossed for the only try.

Jean-Marc Doussain made his Test debut in the recent RWC Final. How many other players have achieved this distinction?Andre van Zyl, South Africa

Doussain's achievement is unique among RWC Final players.

Two players, however, made their Test debuts in RWC Bronze Finals: Richard Webster won his first cap for Wales starting as a flanker in the 22-21 win against Australia in 1987 and Albert Cigagna won his only Test cap playing in the back-row of the French team that beat England to the Bronze in 1995.

Who has captained his nation most often in Tests and who has led his side to most wins?Peter Morgan, Wales

The table below includes Test captaincies of the British/Irish Lions and South American Jaguars (who played Tests against the Springboks in the early 1980s).

Brian O'Driscoll's 81 Tests as captain include one match leading the British/Irish Lions - against New Zealand in 2005. He has led Ireland 80 times to date. Similarly the figures for Hugo Porta and Martin Johnson include (in brackets) their Test captaincies of the Jaguars and the Lions respectively.

Tests

Captain

Career Span

83

J W Smit (South Africa)

2003 to 2011

81 (1)

B G O'Driscoll (Ireland/ Lions)

2002 to 2011

66

R H McCaw (New Zealand)

2004 to 2011

59

W D C Carling (England)

1988 to 1996

59

G M Gregan (Australia)

2001 to 2007

55

J A Eales (Australia)

1996 to 2001

51

S B T Fitzpatrick (New Zealand)

1992 to 1997

48

L Arbizu (Argentina)

1992 to 2003

46 (8)

H Porta (Argentina/ Jaguars)

1971 to 1990

45 (6)

M O Johnson (England/ Lions)

1997 to 2003

45

T Miuchi (Japan)

2002 to 2008

Richie McCaw's figure includes the world record of 58 Test wins as captain of New Zealand. John Smit has 54 Test wins as captain of South Africa.